Operating tables typically have sliding rails along the sides of their table segments, which generally have a rectangular cross section and serve to fasten accessories such as support aids in the desired position on the operating table. Clamping claws may be used to fasten the accessories, being coupled to the particular accessory and mounted on the sliding rail.
In some designs, such a clamping claw is formed as a clamplike part, which is placed on the sliding rail and then fixed in the desired position by a clamping screw. Further modified designs make it possible to swivel clamping claws to a desired place on the sliding rail and thus be fastened more quickly to the sliding rail without involving access from one end of the sliding rail.
Known embodiments of such clamping claws, also known as clamping blocks, are characterized in that a hook-shaped structure reaches across the upper end of the sliding rail, which is rectangular in cross section. In this process, inner flanks of the clamping claw tapering at an acute angle come to bear against the two upper lengthwise edges of the sliding rail, running parallel to each other. The gravity force of the clamping claw, which generally engages the outside of the operating table, rotates the latter until a side flank comes to bear against the upright outer surface of the sliding rail. A clamping element which is moved upward for example via a tommy screw in turn bears against the lower inner edge of the sliding rail with a slanting surface and secures the clamping claw after a prestressing is applied. The transmission of force from the clamping claw to the sliding rail occurs primarily via the edges of the sliding rail. Thus, depending on the design of the edge fillet, this results in different and relatively large surface pressures, which limit the force absorbing capacity of the clamping claw. The connection between clamping claw and sliding rail also may be soft and compliant, since the high load concentration can result in local deformations of the edges. Furthermore, the tolerances of the spacing dimensions and the edge fillets may accumulate (e.g., in the diagonals of the rectangular cross section). These tolerances have to be compensated for by the clamping element.
As for handling, fast clamping systems may be suitable, in which the mounting and prestressing of the clamping element occur by a single movement. This is made difficult by the required large travel of the clamping element.
The above explained problems are magnified in that the sliding rails in use are very different from each other in their dimensions and fillets. It has therefore been difficult thus far to provide a clamping claw which enables a simple and precise mounting of accessories on an operating table regardless of the particular sliding rail used.